Kubernetes集群中，Node异常时Pod状态分析

// delete and recreate failed pods
		if isFailed(replicas[I]) {
			ssc.recorder.Eventf(set, v1.EventTypeWarning, "RecreatingFailedPod",
				"StatefulSetPlus %s/%s is recreating failed Pod %s",
				set.Namespace,
				set.Name,
				replicas[I].Name)
			if err := ssc.podControl.DeleteStatefulPlusPod(set, replicas[I]); err != nil {
				return &status, err
			}
			if getPodRevision(replicas[I]) == currentRevision.Name {
				status.CurrentReplicas—
			}
			if getPodRevision(replicas[I]) == updateRevision.Name {
				status.UpdatedReplicas—
			}
			status.Replicas—
			replicas[I] = newVersionedStatefulSetPlusPod(
				currentSet,
				updateSet,
				currentRevision.Name,
				updateRevision.Name,
				i)
		}

// BeforeDelete tests whether the object can be gracefully deleted.
// If graceful is set, the object should be gracefully deleted.  If gracefulPending
// is set, the object has already been gracefully deleted (and the provided grace
// period is longer than the time to deletion). An error is returned if the
// condition cannot be checked or the gracePeriodSeconds is invalid. The options
// argument may be updated with default values if graceful is true. Second place
// where we set deletionTimestamp is pkg/registry/generic/registry/store.go.
// This function is responsible for setting deletionTimestamp during gracefulDeletion,
// other one for cascading deletions.
func BeforeDelete(strategy RESTDeleteStrategy, ctx context.Context, obj runtime.Object, options *metav1.DeleteOptions) (graceful, gracefulPending bool, err error) {
	objectMeta, gvk, kerr := objectMetaAndKind(strategy, obj)
	if kerr != nil {
		return false, false, kerr
	}
	if errs := validation.ValidateDeleteOptions(options); len(errs) > 0 {
		return false, false, errors.NewInvalid(schema.GroupKind{Group: metav1.GroupName, Kind: "DeleteOptions"}, "", errs)
	}
	// Checking the Preconditions here to fail early. They'll be enforced later on when we actually do the deletion, too.
	if options.Preconditions != nil && options.Preconditions.UID != nil && *options.Preconditions.UID != objectMeta.GetUID() {
		return false, false, errors.NewConflict(schema.GroupResource{Group: gvk.Group, Resource: gvk.Kind}, objectMeta.GetName(), fmt.Errorf("the UID in the precondition (%s) does not match the UID in record (%s). The object might have been deleted and then recreated", *options.Preconditions.UID, objectMeta.GetUID()))
	}
	gracefulStrategy, ok := strategy.(RESTGracefulDeleteStrategy)
	if !ok {
		// If we're not deleting gracefully there's no point in updating Generation, as we won't update
		// the obcject before deleting it.
		return false, false, nil
	}
	// if the object is already being deleted, no need to update generation.
	if objectMeta.GetDeletionTimestamp() != nil {
		// if we are already being deleted, we may only shorten the deletion grace period
		// this means the object was gracefully deleted previously but deletionGracePeriodSeconds was not set,
		// so we force deletion immediately
		// IMPORTANT:
		// The deletion operation happens in two phases.
		// 1. Update to set DeletionGracePeriodSeconds and DeletionTimestamp
		// 2. Delete the object from storage.
		// If the update succeeds, but the delete fails (network error, internal storage error, etc.),
		// a resource was previously left in a state that was non-recoverable.  We
		// check if the existing stored resource has a grace period as 0 and if so
		// attempt to delete immediately in order to recover from this scenario.
		if objectMeta.GetDeletionGracePeriodSeconds() == nil || *objectMeta.GetDeletionGracePeriodSeconds() == 0 {
			return false, false, nil
		}
		...
	}
	...
}